This invention relates to a dispenser for an ion source.
Ion sources are used in industry for material processing and surface analysis. The ion beam produced by these sources may be generated in various ways. The type of ion source with which the present invention is concerned is one in which a film of liquid metal on the surface of a needle electrode is subjected to an electric field which produces a source of ions which latter can then be extracted from the liquid metal by electric field emission. In such ions sources the liquid metal to be ionised is stored in a temporary reservoir surrounding the rear end of the needle, and flows to the tip of the needle, where the ionisation takes place, by surface tension. The metal in the reservoir is heated to a temperature sufficient to keep the metal in the liquid state but not too great as to cause the metal to vapourise. Obviously, the exact temperature depends on the characteristics of the particular metal being used.